In view of numerous factors such as higher energy prices and environmental concerns, the production of value-added gaseous products from lower-fuel-value carbonaceous feedstocks, such as biomass, coal and petroleum coke, is receiving renewed attention. The catalytic gasification of such materials to produce methane and other value-added gases is disclosed, for example, in U.S. Pat. No. 3,828,474, U.S. Pat. No. 3,998,607, U.S. Pat. No. 4,057,512, U.S. Pat. No. 4,092,125, U.S. Pat. No. 4,094,650, U.S. Pat. No. 4,204,843, U.S. Pat. No. 4,468,231, U.S. Pat. No. 4,500,323, U.S. Pat. No. 4,541,841, U.S. Pat. No. 4,551,155, U.S. Pat. No. 4,558,027, U.S. Pat. No. 4,606,105, U.S. Pat. No. 4,617,027, U.S. Pat. No. 4,609,456, U.S. Pat. No. 5,017,282, U.S. Pat. No. 5,055,181, U.S. Pat. No. 6,187,465, U.S. Pat. No. 6,790,430, U.S. Pat. No. 6,894,183, U.S. Pat. No. 6,955,695, US2003/0167961A1, US2006/0265953A1, US2007/000177A1, US2007/083072A1, US2007/0277437A1 and GB 1599932.
Petroleum coke is a generally solid carbonaceous residue derived from the delayed coking or fluid coking a carbon source such as a crude oil residue, and the coking processes used for upgrading oil sand. Petroleum cokes, in general, have poor gasification reactivity, particularly at moderate temperatures, due to their highly crystalline carbon and elevated levels of organic sulfur derived from heavy-gravity oil. Use of catalysts is necessary for improving the lower reactivity of petroleum cokes, however, certain types of catalysts can be poisoned by the sulfur-containing compounds in the petcokes.
Treatment of petroleum coke alone can have very high theoretical carbon conversion (e.g. 98%), but has its own challenges regarding maintaining bed composition, fluidization of the bed in the gasification reactor, control of possible liquid phases and agglomeration of the bed in the gasification reactor and char withdrawal. Additionally, petroleum coke has inherently low moisture content, and a very low water soaking capacity to allow for conventional catalyst impregnation methods. Therefore, methods and compositions are needed which can support and provide a gasification catalyst for the gasification of petroleum coke.